Electronic smoking article

ABSTRACT

An electronic smoking article includes a liquid aerosol formulation, a heater operable to at least partially volatilize the liquid aerosol formulation and form an aerosol and a tubular filter segment downstream of the heater. The tubular filter segment is operable to selectively filter aerosol particles and vapors from the aerosol.

CROSS REFERENCE TO RELATED APPLICATION

This application is a Continuation of U.S. application Ser. No.15/398,165, filed Jan. 4, 2017, which is a continuation of Ser. No.14/332,897 filed Jul. 16, 2014, which claims priority under 35 U.S.C. §119(e) to U.S. provisional Application No. 61/857,904, filed on Jul. 24,2013, the entire contents of each of which are incorporated herein byreference thereto.

WORKING ENVIRONMENT

Many of the embodiments disclosed herein include electronic smokingarticles operable to deliver liquid from a liquid supply reservoir to aheater. The heater volatilizes (aerosolizes) a liquid to form anaerosol.

SUMMARY OF SELECTED FEATURES

An electronic smoking article operable to produce an aerosol includes aliquid aerosol formulation; a heater operable to at least partiallyvolatilize the liquid aerosol formulation and form an aerosol; and atubular filter segment downstream of the heater, the tubular filtersegment operable to selectively filter aerosol particles and vapors fromthe aerosol, whereby a particle size distribution of the aerosol ismodified.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an electronic smoking article constructedaccording to the teachings herein.

FIG. 2 is a cross-sectional view of an electronic smoking articleaccording to a first embodiment.

FIG. 3 is a cross-sectional view of another embodiment of an electronicsmoking article according to a second embodiment.

FIG. 4 is a cross-sectional view of an electronic smoking articleaccording to a third embodiment.

FIG. 5 is a perspective view of a tubular filter segment as describedherein.

FIG. 6 is a cross-sectional view of an electronic smoking articleaccording to a fourth embodiment including the tubular filter segment ofFIG. 5.

FIG. 7 is a perspective view of a detachable tubular filter segment.

FIG. 8 is a cross-sectional view of an electronic smoking articleaccording to a fifth embodiment including the detachable tubular filtersegment of FIG. 7.

FIG. 9 is an abbreviated, cross-sectional view of an electronic smokingarticle according to a sixth embodiment including a tubular filtersegment and a mechanical airflow convertor (MAC) insert.

FIG. 10 is a representation of the effects achieved of using tubularfilter segments of differing internal diameters.

FIG. 11 is a representation of the effects of using differing spacings(x) between the tubular filter segment and the source of the aerosol.

DETAILED DESCRIPTION

An electronic smoking article includes a liquid supply source(reservoir) containing a liquid aerosol formulation. The liquid aerosolformulation is delivered to a heater where the liquid aerosolformulation is heated, volatilized, and forms an aerosol. As usedherein, the term “electronic smoking article” is inclusive of all typesof electronic smoking articles, regardless of form, size or shape,including electronic cigarettes, electronic cigars, electronic pipes,electronic hookahs and the like. The liquid aerosol formulation caninclude nicotine or be nicotine free. Moreover, the liquid aerosolformulation can include tobacco flavors or instead, or in combinationinclude other suitable flavors.

Preferably, the aerosol passes through a tubular filter segment afterformation to selectively filter aerosol particles and vapors, eluteflavor and/or otherwise modify the aerosol composition. While notwishing to be bound by theory, it is believed that the tubular filtersegment selectively filters out smaller particles and vapor phasecomponents from the aerosol as the aerosol passes through the tubularfilter segment, while larger particles are maintained centrally withinthe aerosol flow as the aerosol passes through the tubular filtersegment.

Preferably, the tubular filter segment (TFS) 600 is located downstreamof the heater in an electronic smoking article 60 as shown in FIGS. 2,3, 4, 6, 8 and 9. As shown in FIG. 1, the electronic smoking article 60comprises a replaceable cartridge (or first section) 70 and a reusablefixture (or second section) 72, which are coupled together at a threadedjoint 74 or by other convenience such as a snug-fit, snap-fit, detent,clamp and/or clasp.

As shown in FIG. 3, the first section 70 can house a mouth-end insert20, a capillary aerosol generator including a capillary (capillary tube)18, a heater 19 to heat at least a portion of the capillary 18, areservoir 14 and optionally a valve 40. Alternatively, as shown in FIG.4, the first section 70 can house a mouth end insert 20, a heater 319, aflexible, filamentary wick 328 and a reservoir 314 as discussed infurther detail below.

The second section 72 can house a power supply 12 (shown in FIGS. 2, 3and 4), control circuitry 11, and optionally a puff sensor 16 (shown inFIGS. 3 and 4). The threaded portion 74 of the second section 72 can beconnected to a battery charger when not connected to the first section70 for use so as to charge the battery.

As shown in FIG. 2, the electronic smoking article 60 can also include amiddle section (third section) 73, which can house the reservoir 14,heater 19 and valve 40. The middle section 73 can be adapted to befitted with a threaded joint 74′ at an upstream end of the first section70 and a threaded joint 74 at a downstream end of the second section 72.In this embodiment, the first section 70 houses the mouth-end insert 20,while the second section 72 houses the power supply 12 and controlcircuitry.

Preferably, the first section 70, the second section 72 and the optionalthird section 73 include an outer cylindrical housing 22 extending in alongitudinal direction along the length of the electronic smokingarticle 60. Moreover, in one embodiment, the middle section 73 isdisposable and the first section 70 and/or second section 72 arereusable. In another embodiment, the first section 70 can also bereplaceable so as to avoid the need for cleaning the capillary 18 and/orheater 19. The sections 70, 72, 73 can be attached by threadedconnections whereby the middle section 73 can be replaced when liquid inthe reservoir 14 is used up.

It is contemplated that the housing may be a single, unitary elementwithout any threaded connections.

As shown in FIG. 2, the outer cylindrical housing 22 can include acutout or depression 102 which allows a smoker (vaporer) to manuallyapply pressure to the reservoir 14. Preferably, the outer cylindricalhousing 22 is flexible and/or compressible along the length thereof andfully or partially covers the reservoir 14. The cutout or depression 102can extend partially about the circumference of the outer cylindricalhousing 22. Moreover, the reservoir 14 is compressible such that whenpressure is applied to the reservoir, liquid is pumped from thereservoir 14 to the capillary 18. A pressure activated switch 44 can bepositioned beneath the reservoir 14. When pressure is applied to thereservoir 14 to pump liquid, the switch is also pressed and a heater 19is activated. The heater 19 can be a portion of the capillary 18.

In the embodiment of FIG. 2, the reservoir 14 is a tubular, elongatebody formed of an elastomeric material so as to be flexible and/orcompressible when squeezed. Preferably, the elastomeric material can beselected from the group consisting of silicone, plastic, rubber, latex,and combinations thereof.

Preferably, the compressible reservoir 14 has an outlet 16 which is influid communication with a capillary 18 so that when squeezed, thereservoir 14 can deliver a volume of liquid material to the capillary18. Simultaneous to delivering liquid to the capillary, the power supply12 is activated upon application of manual pressure to the pressureswitch and the capillary 18 is heated to form a heated section whereinthe liquid material is volatilized. Upon discharge from the heatedcapillary 18, the volatilized material expands, mixes with air and formsan aerosol.

Preferably, the reservoir 14 extends longitudinally within the outercylindrical housing 22 of the first section 70 (shown in FIGS. 3 and 4)or the middle section 73 (shown in FIG. 2). Moreover, the reservoir 14comprises a liquid aerosol formulation which is volatilized when heatedand forms an aerosol when discharged from the capillary 18.

In the preferred embodiments shown in FIGS. 2 and 3, the capillary 18includes an inlet end 62 in fluid communication with the outlet 16 ofthe reservoir 14, and an outlet end 63 operable to expel volatilizedliquid material from the capillary 18. In a preferred embodiment, asshown in FIGS. 2 and 3, the reservoir 14 may include a valve 40.

As shown in FIG. 2, the valve 40 can be a check valve that is operableto maintain the liquid material within the reservoir, but opens when thereservoir 14 is squeezed and pressure is applied. Preferably, the checkvalve 40 opens when a critical, minimum pressure is reached so as toavoid inadvertent dispensing of liquid material from the reservoir 14 oractivating the heater 19. Once pressure upon the reservoir 14 isrelieved, the valve 40 closes. The heated capillary 18 discharges liquidremaining downstream of the valve 40.

As shown in FIG. 3, in other embodiments, the valve 40 can be a two-wayvalve and the reservoir 14 can be pressurized. For example, thereservoir 14 can be pressurized using a pressurization arrangement 405which applies constant pressure to the reservoir 14. For example,pressure can be applied to the reservoir 14 using an internal orexternal spring and plate arrangement which constantly applies pressureto the reservoir 14. Alternatively, the reservoir 14 can be compressibleand positioned between two plates that are connected by springs or thereservoir 14 could be compressible and positioned between the outerhousing and a plate that are connected by a spring so that the plateapplies pressure to the reservoir 14.

Preferably, the capillary 18 of FIGS. 2 and 3 has an internal diameterof 0.01 to 10 mm, preferably 0.05 to 1 mm, and more preferably 0.05 to0.4 mm. Also preferably, the capillary 18 may have a length of about 5mm to about 72 mm, more preferably about 10 mm to about 60 mm or about20 mm to about 50 mm. In one embodiment, the capillary 18 issubstantially straight. In other embodiments, the capillary 18 is coiledand/or includes one or more bends therein to conserve space and/oraccommodate a long capillary.

In these embodiments, the capillary 18 is formed of a conductivematerial, and thus acts as its own heater 19 by passing current throughthe capillary. The capillary 18 may be any electrically conductivematerial capable of being resistively heated, while retaining thenecessary structural integrity at the operating temperatures experiencedby the capillary 18, and which is non-reactive with the liquid material.Suitable materials for forming the capillary 18 are selected from thegroup consisting of stainless steel, copper, copper alloys, porousceramic materials coated with film resistive material, Inconel®available from Special Metals Corporation, which is a nickel-chromiumalloy, nichrome, which is also a nickel-chromium alloy, and combinationsthereof.

Alternatively, the capillary 18 may be a non-metallic tube such as, forexample, a glass tube having a conductive material capable of beingresistively heated, such as, for example, stainless steel, nichrome orplatinum wire, arranged there along.

Preferably, at least two electrical leads 26 are bonded to a metalliccapillary 18 by brazing or crimping. Preferably, one electrical lead 26is attached to a first, upstream portion 101 of the capillary 18 and asecond electrical lead 26 is attached to a downstream, end portion 104of the capillary 18, as shown in FIGS. 2 and 3.

As noted above, the liquid aerosol formulation can also be used in anelectronic smoking article including a heater 319 and a filamentary wick328 as shown in FIG. 4. The first section 70 includes an outer tube (orcasing) 22 extending in a longitudinal direction and an inner tube (orchimney) 362 coaxially positioned within the outer tube 322. Preferably,a nose portion 361 of an upstream gasket (or seal) 320 is fitted into anupstream end portion 365 of the inner tube 362, while at the same time,an outer perimeter 367 of the gasket 320 provides a liquid-tight sealwith an interior surface 397 of the outer casing 22. The upstream gasket320 also includes a central, longitudinal air passage 315, which opensinto an interior of the inner tube 362 that defines a central channel321. A transverse channel 333 at an upstream portion of the gasket 320intersects and communicates with the central channel 315 of the gasket320. This channel 333 assures communication between the central channel315 and a space 335 defined between the gasket 320 and a threadedconnection 74.

Preferably, a nose portion 393 of a downstream gasket 310 is fitted intoa downstream end portion 381 of the inner tube 362. An outer perimeter382 of the gasket 310 provides a substantially liquid-tight seal with aninterior surface 397 of the outer casing 22. The downstream gasket 310includes a central channel 384 disposed between the central passage 321of the inner tube 362 and the mouth end insert 20.

In this embodiment, the reservoir 314 is contained in an annulus betweenan inner tube 362 and an outer casing 22 and between the upstream gasket320 and the downstream gasket 310. Thus, the reservoir 314 at leastpartially surrounds the central air passage 321. The reservoir 314comprises a liquid material and optionally a liquid storage medium (notshown) operable to store the liquid material therein.

The inner tube 362 has a central air passage 321 extending therethroughwhich houses the heater 319. The heater 319 is in contact with thefilamentary wick 328, which preferably extends between opposing sectionsof the reservoir 314 so as to deliver the liquid aerosol formulationfrom the reservoir to the heater 319.

Preferably, the electronic smoking article 60 of each embodimentdescribed herein also includes at least one air inlet 440. As shown inFIG. 4, the at least one air inlet 440 can be located upstream of theheater 319.

In the embodiments shown in FIGS. 2 and 3, the at least one air inlet440 is arranged downstream of the capillary 18 so as to minimize drawingair along the capillary and thereby avoid cooling of the capillary 18during heating cycles.

The power supply 12 of each embodiment can include a battery arranged inthe electronic smoking article 60. The power supply 12 is operable toapply voltage across the heater 19 associated with the capillary 18, asshown in FIGS. 2 and 3, or the heater 319 associated with thefilamentary wick 328, as shown in FIG. 4. Thus, the heater 19, 319volatilizes liquid material according to a power cycle of either apredetermined time period, such as a 2 to 10 second period.

The battery can be a Lithium-ion battery or one of its variants, forexample a Lithium-ion polymer battery. Alternatively, the battery may bea Nickel-metal hydride battery, a Nickel cadmium battery, aLithium-manganese battery, a Lithium-cobalt battery or a fuel cell. Inthat case, preferably, the electronic smoking article 60 is usable by asmoker until the energy in the power supply is depleted. Alternatively,the power supply 12 may be rechargeable and include circuitry allowingthe battery to be chargeable by an external charging device. The controlcircuitry 11 can be programmable and can include an application specificintegrated circuit (ASIC). In other embodiments, the control circuitry11 can include a microprocessor programmed to carry out functions suchas heating the capillaries and/or operating the valves.

Preferably, the electronic smoking article 60 of each embodiment alsoincludes control circuitry which can be on a printed circuit board 11(shown in FIGS. 2, 3 and 4). The control circuitry 11 can also include aheater activation light 27 that is operable to glow when the heater 19,319 is activated.

As shown in FIGS. 2, 3, 4, 6, 8 and 9 the electronic smoking article 60includes the tubular filter segment 600 at a location downstream of theheater 19, 319. Preferably, the tubular filter segment 600 isconstructed from low density cellulose acetate tow and is a hollowacetate tube (HAT). The tubular filter segment 600 can be about 2 mm toabout 30 mm in length. More preferably, the tubular filter segment 600is about 5 mm to about 25 mm in length (e.g., about 10 to about 20 mm orabout 12 to about 18 mm). Also preferably, the tubular filter segment600 is about 0.5 mm to about 6 mm thick (e.g., about 2 mm to about 5 mmor about 3 mm to about 4 mm). In addition, the outer diameter of thetubular filter segment 600 is about the same or slightly greater than adiameter of the electronic smoking article 60 so as to provide aninterference (snug) fit between the two.

Moreover, as shown in FIGS. 2, 3, 4, 5, 6, 7 and 8, the tubular filtersegment 600 includes a hollow core 602 having a diameter “D” (shown inFIGS. 2 and 5) of about 1 mm to about 6 mm (e.g., about 2 mm to about 5mm or about 3 mm to about 4 mm). In one embodiment, the diameter of thehollow core 602 is uniform along the length of the tubular filtersegment 600. In another embodiment, the hollow core 602 can have adiameter that varies along the length of the tubular filter segment 600.Thus, the aerosol flow can have a straight, bended or twisted path.Different flow paths may contribute to a different degree of potentialfiltration by impaction and also cooling of the aerosol.

Aerosol filtration during smoking (vaping) can be accomplished byimpaction, interception and/or diffusion. Moreover, the tubular filtersegment 600 could have electrostatic filtration mechanisms, which canaid in filtering the aerosol.

The diameter of the hollow core 602 can be chosen so that only a certainsize range of aerosol particles will encounter the tubular filtersegment 600 and be removed from the aerosol flow. Moreover, the distanceof the tubular filter segment 600 from the heater 19, 319 can be chosenbased on the different trajectories of the aerosol tube to producedifferent interactions with the tubular filter segment 600 duringsmoking, and thus different sensory experiences. If the tubular filtersegment 600 is closer to the heater, a smaller amount of the aerosolwill be exposed to the tubular filter segment 600. However, if thetubular filter segment 600 is positioned farther away from the heater, alarger amount of the aerosol will be exposed to the tubular filtersegment 600. Moreover, depending on the thickness and density of thetubular filter segment 600, different degrees of aerosol filtration maybe achieved as the aerosol is passing through or around the periphery ofthe tubular filter segment 600.

In another embodiment, the tubular filter segment 600 can be formed ofporous foam, paper or other cellulosic materials so long as the materialis air transmissive. The tubular filter segment 600 can be made viaother forming techniques such as molding or extruding the tube orforming a tube with a longitudinal seam.

In the preferred embodiment, the tubular filter segment 600 minimizesresistance to draw (RTD) in the electronic smoking article 60 and can beincluded inside the first section 70 during manufacture or can be adetachable tubular filter segment, as shown in FIGS. 7 and 8, foraddition to the electronic smoking article if desired.

As shown in FIGS. 7 and 8, the detachable tubular filter segment 600 caninclude a sleeve portion 604 designed to fit around the outer perimeterof the mouth end of the electronic smoking article 60.

As shown in FIG. 6, the electronic smoking article 60 can include thetubular filter segment 600 at the mouth end of the electronic smokingarticle 60. In other embodiments, shown in FIG. 4, a mouth end insert 20can be positioned downstream of the tubular filter segment 600.Alternatively, the mouth end insert 20 can be positioned upstream of thetubular filter segment 600 as shown in FIG. 8.

In yet another embodiment, as shown in FIG. 9, the electronic smokingarticle 60 can include the tubular filter segment 600 and a mechanicalaerosol converter (MAC) insert 704 as described in commonly owned,co-pending patent application Ser. No. 13/756,067 filed Jan. 31, 2013,the entire content of which is incorporated herein by reference theretofor all purposes. The MAC insert 704 comprises a cylindrical bodyportion 706 having an outer diameter that can be sized to provide asliding fit with the interior surfaces of the outer housing 22 of theelectronic smoking article 60. During smoking and after passing throughthe tubular filter segment 600, the aerosol is drawn into contact with aface 702 of the MAC insert 704. After contacting the face 702 of the MACinsert 704, aerosol is then drawn through the orifices 712 in the MACinsert 704, which are disposed radially about the face 702. A gasket 800having a central orifice 802 can be positioned upstream of the MACinsert 704 so as to focus the aerosol on the face 702. Accordingly,larger particle in the aerosol will impact the face 702 and get filteredout or break up prior to the aerosol being drawn out of the electronicsmoking article. It is also believed that the tubular filter section 600assists in thermal transfer thus cooling down the aerosol and improvingthe sensorial attributes thereof.

In a preferred embodiment, additives including flavors and/or aerosolmodifiers can be applied to the tubular filter segment 600 so thatadditives are eluted into the aerosol as the aerosol passestherethrough. For example, the additives can be applied as a coating onthe inner surface of the hollow core 602, as a coating 606 on an outersurface of the tubular filter segment 600 (shown in FIG. 8) or theflavors and/or aerosol modifiers can be impregnated in the tubularfilter segment 600. The additives can be microencapsulated with watersoluble materials having varying levels of water solubility so as toprovide controlled release of the additive over a period of time.Moreover, the tubular filter segment 600 can include impregnatedadditives and an additive coating. The coating material can include thesame additive as that contained in the tubular filter segment 600 or adifferent additive. By including an additive-containing coating alongwith the additives impregnated in the tubular filter segment 600,release of the additives can be staggered during smoking and/or multipleadditives can be delivered. The heat of the aerosol could also help topromote release of additives from the tubular filter segment 600.

As used herein, the term “additive” means any material which modifiesthe characteristics of the electronic smoking article 60 when theelectronic smoking article 60 is vaped. Any appropriate additivematerial or combination of materials may be contained in the tubularfilter segment 600. Such additive materials include flavor materials,aromatic materials, pH modifying agents (e.g., buffers and/or acids),chemesthesis agents including cooling agents and warming agents, carbondioxide formers, commercially available flavor systems, nicotine inliquid, salt or powder form, and other aerosol modifiers.

As used herein, the term “flavor material” means any liquid or solidflavor containing material or formulation that can release flavorsand/or aromas into the aerosol stream. Suitable flavors or flavoringsinclude, but are not limited to, menthol, mint, such as peppermint andspearmint, chocolate, licorice, citrus and other fruit flavors, gammaoctalactone, vanillin, ethyl vanillin, breath freshener flavors, spiceflavors such as cinnamon, methyl salicylate, linalool, bergamot oil,geranium oil, lemon oil, ginger oil, and tobacco flavor. Other suitableflavors may include flavor compounds selected from the group consistingof an acid, an alcohol, an ester, an aldehyde, a ketone, a pyrazine,combinations or blends thereof and the like.

The flavor material can be in the form of particles, granules, fibers,capsules, microcapsules, powders, crushed plant material, aromaticbarks, seeds, pieces of dried fruits and/or root material, or any othersuitable form. For example, the flavor material can include tobaccobeads, tobacco powder or tobacco particles (filler), flavor beads,mentholated flavor beads, flavor capsules and other flavor materials asused in traditional tobacco smoke filters.

Suitable flavor materials can be non-volatile or volatile and can bedelivered to the mouth via the condensation of the aerosol in the filterfollowed by entrapment and/or dissolution of the flavor material indroplets and/or deposition of the droplets to the tongue of the smokerduring a puff. Another potential mechanism can be the physicaldisplacement of liquid or particulate additives by the air flow. Thedroplets can consist of constituents used to form the aerosol includingpropylene glycol, glycerin, water and optionally nicotine. The flavormaterial can be released into the aerosol and/or can be delivered to asmoker's mouth via contact with moisture from the smoker's lips.

The flavor materials can provide a bitter taste. Suitable compoundswhich provide a bitter taste include, without limitation, caffeine,denatonium benzoate, theobromine, quinine, and naringin.

The flavor materials can provide a sour taste. Suitable compounds whichprovide a sour taste include, without limitation, citric acid, malicacid, succinic acid and tartaric acid.

The flavor materials can provide a salty taste. Suitable compounds whichprovide a salty taste include, without limitation, sodium chloride andpotassium chloride.

The flavor materials can provide a sweet taste. Suitable compounds whichprovide a sweet taste include, without limitation, carbohydrates,including sucrose, and high intensity sweeteners, including sucraloseand saccharin.

The flavor materials can provide umami and mouth feel. Suitablecompounds which provide umami and mouth feel include, withoutlimitation, monosodium glutamate, gamma-glutamyl peptides, such asgamma-glutamycysteine-beta-alanine, (R)-strombine.

In one embodiment, the additive can be a chemesthesis agent and/or canbe chosen to alter the mouthfeel of the aerosol. For example, theadditive can be a chemesthesis agent that provides a warm, tinglingsensation and/or a cooling sensation. Additives such as capsaicin,piperine, alpha-hydroxy-sanshool, and (8)-gingerole can be included toprovide a warm, tingling or burning sensation. Additives includingmenthol, menthyl lactate, WS-3 (N-Ethyl-p-menthane-3-carboxamide), WS-23(2-Isopropyl-N,2,3-trimethylbutyramide) and Evercool 180™ can beincluded to provide a cooling sensation. In addition, the additive caninclude extracts, such as coffee extract, red pepper extract, gingerextract and peppermint oil.

During smoking, as aerosol travels through the tubular filter segment600, larger particles remain centrally located in the flow path whilesmaller particles and vapor phase components diffuse to the periphery ofthe flow path and contact the tubular filter segment. Accordingly, thesmaller particles and vapor phase components can be filtered out fromthe aerosol. When additives are impregnated in and/or coated on thetubular filter segment, the additives can be at least partially elutedinto the aerosol for delivery to the smoker.

Preferably, the tubular filter segment 600 is located downstream of theheater 19, 319 so that minimum heat exposure is experienced by theadditives. Thus, preferably, the tubular filter segment 600 is locatedso that the tubular filter segment 600 and/or additives containedtherein are not exposed to temperatures above about 150° C.

For example, the tubular filter segment can be a hollow acetate tube(HAT) having a length of about 7 mm, an outer diameter of about 7 mm andan inner diameter of about 5 mm. The HAT can be treated with a solutionof 10% triacetin and 10% citric acid and placed at the exit of the innerchannel 321 (shown in FIG. 4). Aerosol particles with differenttrajectories will interact with the HAT differently and at differentphysical locations. Chemical analysis of the HAT after smoking showssignificant amount of nicotine, indicating filtration of at least somevapor phase nicotine and aerosol particles by the HAT. Moreover, it isbelieved that the vapor phase nicotine can interact with the citric acidapplied to the HAT so as to reduce harshness and improve the sensoryexperience.

As shown in FIGS. 2, 3, 4, and 8, the electronic smoking article 60 canfurther include the mouth-end insert 20 having at least two off-axis,preferably diverging outlets 21. Preferably, the mouth-end insert islocated downstream of the tubular filter segment 600. In otherembodiments, as shown in FIG. 8, the tubular filter segment 600 can bedownstream of the mouth-end insert 20.

Preferably, the mouth-end insert 20 includes at least two divergingoutlets 21. (e.g. 3, 4, 5, or preferably 6 to 8 outlets or more).Preferably, the outlets 21 of the mouth-end insert 20 are located atends of off-axis passages 23 and are angled outwardly in relation to thelongitudinal direction of the electronic smoking article 60 (i.e.,divergently). As used herein, the term “off-axis” denotes at an angle tothe longitudinal direction of the electronic smoking article.

In a preferred embodiment, the electronic smoking article 60 is aboutthe same size as a conventional smoking article. In some embodiments,the electronic smoking article 60 can be about 80 mm to about 110 mmlong, preferably about 80 mm to about 100 mm long and about 7 mm toabout 8 mm in diameter. For example, in an embodiment, the electronicsmoking article is about 84 mm long and has a diameter of about 7.8 mm.

The outer cylindrical housing 22 of the electronic smoking article 60may be formed of any suitable material or combination of materials.

Preferably, the liquid aerosol formulation for use in each of theelectronic smoking articles 60 described herein includes at least oneaerosol former, water, and flavors. The liquid aerosol formulation caninclude nicotine or be nicotine free. Moreover, the liquid aerosolformulation can include tobacco flavors or other suitable flavors.

In the preferred embodiment, the at least one aerosol former is selectedfrom the group consisting of propylene glycol, glycerin and combinationsthereof. Preferably, the at least one aerosol former is included in anamount ranging from about 40% by weight based on the weight of theliquid formulation to about 90% by weight based on the weight of theliquid formulation (e.g., about 50% to about 80%, about 55% to about 75%or about 60% to about 70%).

Preferably, the liquid formulation also includes water. Water can beincluded in an amount ranging from about 5% by weight based on theweight of the liquid formulation to about 20% by weight based on theweight of the liquid formulation, more preferably in an amount rangingfrom about 10% by weight based on the weight of the liquid formulationto about 15% by weight based on the weight of the liquid formulation.

The liquid aerosol formulation optionally includes at least oneflavorant in an amount ranging from about 0.2% to about 15% by weight(e.g., about 1% to about 12%, about 2% to about 10%, or about 5% toabout 8%). The at least one flavorant can be a natural flavorant or anartificial flavorant. Preferably, the at least one flavorant is selectedfrom the group consisting of tobacco flavor, menthol, wintergreen,peppermint, herb flavors, fruit flavors, nut flavors, liquor flavors,and combinations thereof.

Referring to FIGS. 10a, 10b, and 10c , a representation is providedwherein the source of aerosol is designated as 63, 163 which arerepresented as the discharge orifice 63 of the heated capillary or thedischarge orifice 163 of the inner tube shown in FIGS. 6 and 8.Progressing from FIGS. 10a to 10c , as the inner diameter of the TFS 600is reduced, a greater proportion of the aerosol passes through the bodyof the TFS 600, so as to reduce the population of larger particles inthe aerosol that leaves the electronic smoking article 60. Particle sizedistribution of the aerosol can be adjusted accordingly. Likewise, nowreferring to FIGS. 11a, 11b, and 11c , as a distance x between thesource of aerosol 63,163 and the TFS 600 is decreased (progressing fromFIG. 11a to 11c , a smaller proportion of the aerosol passes through thebody of the TFS 600 so as to lessen impact of the TFS 600 on theparticle size distribution of the aerosol which ultimately leaves theelectronic smoking article 60.

When the word “about” is used in this specification in connection with anumerical value, it is intended that the associated numerical valueinclude a tolerance of ±10% around the stated numerical value. Moreover,when reference is made to percentages in this specification, it isintended that those percentages are based on weight, i.e., weightpercentages.

Moreover, when the words “generally” and “substantially” are used inconnection with geometric shapes, it is intended that precision of thegeometric shape is not required but that latitude for the shape iswithin the scope of the disclosure. When used with geometric terms, thewords “generally” and “substantially” are intended to encompass not onlyfeatures which meet the strict definitions but also features whichfairly approximate the strict definitions.

It will now be apparent that a new, improved, and nonobvious electronicsmoking article has been described in this specification with sufficientparticularity as to be understood by one of ordinary skill in the art.Moreover, it will be apparent to those skilled in the art that numerousmodifications, variations, substitutions, and equivalents exist forfeatures of the electronic smoking article which do not materiallydepart from the spirit and scope of the invention. Accordingly, it isexpressly intended that all such modifications, variations,substitutions, and equivalents which fall within the spirit and scope ofthe invention as defined by the appended claims shall be embraced by theappended claims.

We claim:
 1. A cartridge of an electronic article comprising: a housing;a heater in the housing, the heater configured to heat a formulation toform a vapor; and a filter formed of a hollow acetate tube including ahollow inner core, the filter having a length, the hollow inner corehaving an inner diameter that varies along an entirety of the length ofthe filter, the filter between the heater and a mouth end of thecartridge.
 2. The cartridge of claim 1, wherein the length of the filterranges from about 2 mm to about 30 mm.
 3. The cartridge of claim 1,wherein the filter is detachable from the cartridge.
 4. The cartridge ofclaim 1, wherein the filter includes a sleeve configured to attach thefilter to the cartridge.
 5. The cartridge of claim 1, furthercomprising: a mouthpiece at the mouth end of the cartridge, the filterbetween the heater and the mouthpiece.
 6. The cartridge of claim 1,wherein the filter comprises: at least one additive.
 7. The cartridge ofclaim 6, wherein the at least one additive includes flavor, an aerosolmodifier, an aromatic material, a pH modifying agent, a chemesthesisagent, or any combination thereof.
 8. The cartridge of claim 6, whereinthe at least one additive is impregnated in the filter.
 9. The cartridgeof claim 6, wherein the filter comprises: a coating on at least onesurface of the filter, the at least one additive in the coating.
 10. Thecartridge of claim 6, wherein the at least one additive is encapsulated.11. The cartridge of claim 6, wherein the at least one additive isdispersed substantially uniformly throughout the filter.